The gathering of cardinals in the Vatican was overshadowed by farce when a German man masquerading as a bishop tried to infiltrate the meeting.

Ralph Napierski, a self-appointed bishop from an apparently fictional order called Corpus Dei, managed to get through a checkpoint manned by Swiss Guards but was stopped before entering the Paul VI Hall, where the cardinals were gathering.

Dressed in fake bishop's vestments, Mr Napierski smiled to photographers as he mixed with more than 140 cardinals from around the world as they filed into the hall to discuss the challenges facing the church and possible "papabili" or papal candidates.

Unlike the cardinals, who wore their distinctive red skull caps, the impostor wore a black fedora-style hat. After being rumbled, Mr Napierski was escorted away from the gathering by Swiss Guards.

He said he was a member of the "Italian Orthodox Church", which does not exist, and said the Catholic Church had made grave errors by allowing priests accused of child abuse to move around different parishes.

On his website, Mr Napierski claims that he is a founder of the Corpus Dei Catholic order.